When you getting this error ?

http://help.openerp.com/question/9285/account-and-period-must-belong-to-the-same-company/

I set the multi company environment and created two chart of accounts for parent and child. I created separate journals and periods for the child account. When I am to create a new invoice from child company, I was able to create it and save it. But couldn't validate it. The above mentioned error occurred.

Try this https://doc.openerp.com/book/3/3_7/invoicing/

Thanks jack

Thanks Prakash